A fatal case report of sepsis caused by Robinsoniella sp.

Robinsoniella species are anaerobic, spore-forming, Gram-positive bacilli that are rarely associated with human infections because of their slow growth and the limitations of conventional identification methods. We describe a fatal case of sepsis in an 84-year-old woman with hypertension, diabetes, and chronic renal insufficiency. During hospitalization, she developed impaired consciousness, polymicrobial infections, and multiple organ failure. Despite aggressive antimicrobial and supportive treatment, her condition deteriorated, leading to death. This study identified a Robinsoniella isolate (designated Rp5645) by 16S rRNA gene sequencing, showing 98.35% similarity to R. peoriensis PPC31. As this value falls below the accepted species-level threshold, Rp5645 may represent a novel Robinsoniella species. Unfortunately, the isolate lost viability before further genomic or phenotypic studies could be performed. This outcome illustrates the technical challenges in recovering and preserving fastidious anaerobes and underscores the crucial role of rapid molecular identification in confirming rare pathogens. This case broadens the clinical spectrum of Robinsoniella infections and highlights its potential pathogenic capacity, particularly in older or immunocompromised patients. It also emphasizes the need for timely molecular characterization to prevent the loss of valuable data from uncommon clinical isolates.